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(Circulation. 2006;114:1315-1320.)
© 2006 American Heart Association, Inc.
Controversies in Cardiovascular Medicine |
From The Heart Research Institute and the Department of Medicine, University of Sydney, Sydney (P.J.B., K.-A.R.), and the Department of Medicine, University of Melbourne, Melbourne (K.-A.R.), Australia.
Correspondence to Professor Philip Barter, The Heart Research Institute, 145 Missenden Rd, Camperdown, NSW 2050, Australia. E-mail barterp{at}hri.org.au
| Introduction |
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Response by Gotto p 1320
On the basis of the available evidence base, most current guidelines recommend the use of statins in all high-risk people, with high risk being variously defined as those either with existing CV disease or with a calculated 5-year risk that is comparable to that in people with manifest disease.
Given the evidence of efficacy and safety, it has been suggested that statins should be provided over the counter (OTC) in pharmacies without the need for a prescription to make them accessible to a much wider group of people. This approach has already been adopted in the United Kingdom, where low-dose (10 mg) simvastatin is now available OTC. The question arises: Is it desirable to make statins available OTC?
This article argues against making statins available OTC on 3 grounds: (1) The risk of adverse effects may no longer be outweighed by the benefits if statins are used in people at low CV risk; (2) high-risk people may not achieve the low LDL targets shown to be desirable to maximize risk reduction; and (3) other lipid abnormalities such as a low high-density lipoprotein (HDL) cholesterol may not be identified or treated.
| Balance Between Benefits and Adverse Effects |
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The best-known serious adverse effect of statins is a myopathy that, in some people, may result in potentially fatal rhabdomyolysis. Significant myopathy is relatively uncommon, occurring in <0.5% of patients taking these agents.1 It is dose dependent and is a major factor in determining what should be the highest recommended dose of each member of the class. Progression of myopathy to the potentially fatal condition of rhabdomyolysis is a rare occurrence, with a reported frequency of 1 in 30 000 to 100 000 patient-years of exposure.1 Rhabdomyolysis has been observed with all statins, although its frequency varies with the different members of the class.2,3 The higher relative frequency of rhabdomyolysis associated with use of cerivastatin4 led to this agent being withdrawn from the market.
There are well-documented circumstances in which the risk of rhabdomyolysis in people taking statins is increased59 (Table). The best known of these instances relates to the potential of statins to interact adversely when coadministered with fibrates5,6 and macrolide antibiotics such as erythromycin.7 The risk of serious myopathy associated with the use of statins also is increased in people taking cyclosporine after renal or heart transplant.8 Although it is most unlikely that a transplant patient would use OTC statins, there is a real danger that someone taking OTC statins could inadvertently be prescribed an agent such as erythromycin. The possibility of this occurring in someone at low risk of having a CV event creates a setting in which the benefit-to-risk ratio may be unacceptably low.
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Adverse effects of statins also are greater in the elderly,9 in whom the potential dangers of OTC statins may be especially high. The fact that many elderly people are already taking many other medications may add to the risk of serious adverse effects associated with unmonitored use of statins in such people.
The most common argument used to support the availability of OTC statins is that doing so will make these agents accessible to a much wider range of people than is recommended by current guidelines. It is argued that these agents are so safe and so effective that there is no justification for limiting them only to high-risk people. However, before accepting this proposition, we should consider just how great the potential benefits are of using statins in someone whose CV risk is low.
Consider someone whose 5-year CV risk is 2%. Treatment with, for example, 20 mg simvastatin would be predicted to reduce the concentration of LDL cholesterol by
40 mg/dL. According to a recent meta-analysis,10 an LDL cholesterol reduction of this magnitude would translate into an
20% reduction in CV risk, thus converting the 5-year CV risk in this person from 2% to 1.6%. The risk of a serious adverse event associated with the unmonitored use of a statin in such a person may well exceed this small benefit. The reality is that it is impossible to calculate either the benefit-to-risk ratio or the cost-effectiveness of OTC statin in people whose CV risk is low. If, however, CV risk is high, it is essential that therapy be closely monitored to ensure that recommended LDL cholesterol targets are achieved.
| Failure to Achieve Recommended LDL Targets |
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The CV risk reduction associated with statin use is a direct function of both the magnitude of the reduction in concentration of LDL cholesterol10 (Figure 1) and the level of LDL cholesterol achieved by the treatment13 (Figure 2). There is growing consensus that if a statin is indicated, it should be used in a dose sufficient to achieve levels of LDL cholesterol that are very much lower than were previously considered to be ideal.14 Such targets are most unlikely to be achieved in people taking the low doses of statins that are likely to be available OTC.
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The evidence base in support of aggressive LDL cholesterol lowering is huge. It includes studies that have involved >100 000 people in long-term, large-scale, controlled clinical trials. These trials have been conducted in settings of primary and secondary prevention, in men and women spanning a wide range of ages, in diabetics and nondiabetics, in those with and without hypertension, and in people with a wide range of baseline levels of LDL cholesterol.
A recent meta-analysis of data from 90 056 participants in 14 randomized trials of statins was reported by the Cholesterol Treatment Trialists collaborators.10 This analysis was motivated by the fact that, in isolation, none of the individual trials had sufficient power to assess the precise relationship between the magnitude of LDL lowering and the extent of CV event reduction. The database for the meta-analysis included 8186 deaths and 14 348 major CV events. The reductions in LDL cholesterol in these trials ranged from 13 to 68 mg/dL. Overall, for each 40-mg/dL reduction in LDL cholesterol, there was a 12% reduction in all-cause mortality, a 23% reduction in myocardial infarction or coronary death, a 24% reduction in the need for coronary revascularization, and a 17% reduction in fatal or nonfatal stroke. All of these reductions were statistically highly significant. The reduction in major vascular events was predicted by the absolute reduction in LDL cholesterol achieved. It was concluded on the basis of this meta-analysis that prolonged statin treatment with substantial LDL cholesterol reductions should be considered in all patients at high risk of any type of major vascular event.
The meta-analysis established beyond reasonable doubt that CV event reduction is proportional to the magnitude of the LDL lowering.10 There is also growing evidence that the actual level of LDL cholesterol achieved during treatment with statins is predictive of CV events. This was best shown in the recently reported Treating to New Targets (TNT) trial.13 This trial was designed to assess the efficacy and safety of treating people with stable coronary heart disease (CHD) to LDL cholesterol levels significantly below 100 mg/dL. A total of 10 001 patients with clinically manifest CHD were randomized to double-blind therapy with atorvastatin 10 or 80 mg/d and followed up for a median of 4.9 years. The primary end point was a major CV event defined as CHD death, nonfatal nonprocedure-related myocardial infarction, resuscitated cardiac arrest, and fatal or nonfatal stroke.
The mean LDL cholesterol level achieved during treatment was 77 mg/dL with atorvastatin 80 mg and 101 mg/dL with atorvastatin 10 mg. A primary event was recorded in 434 patients (8.7%) in the group receiving atorvastatin 80 mg and in 548 patients (10.9%) in the 10-mg group. This 22% reduction in the risk of major CV events in the 80-mg group was statistically highly significant (P<0.001). There was also a significant reduction in stroke (fatal plus nonfatal) in the 80-mg group compared with the 10-mg group. Stroke occurred in 117 patients (2.3%) receiving atorvastatin 80 mg and 155 patients (3.1%) receiving atorvastatin 10 mg, representing a 25% reduction (P<0.001) in the 80-mg group. There was no difference in total mortality between the 2 groups: 284 patients (5.7%) died in the group receiving atorvastatin 80 mg and 282 (5.6%) in the group receiving atorvastatin 10 mg, possibly reflecting the fact that the mortality in this trial was considerably lower in both the 10-mg and 80-mg groups than had been reported in any of the previously published secondary prevention trials with statins.
The TNT trial added to a mounting body of evidence that lowering LDL cholesterol to levels well below the previously recommended target of 100 mg/dL results in a clinically and statistically significant additional reduction in the risk of future CV events.
A similar conclusion was drawn from the results of the Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) trial, in which the effects of low-dose simvastatin were compared with high-dose atorvastatin.15 The low-dose simvastatin group achieved an LDL cholesterol of 104 mg/dL compared with 84 mg/dL in the high-dose atorvastatin group. The primary end point of the TNT trial (major CV events, defined as the combination of CHD death, nonfatal nonprocedure-related myocardial infarction, resuscitated cardiac arrest, and fatal or nonfatal stroke) was prespecified as a secondary end point in the IDEAL study. Consistent with the results in TNT, the combined end point of major CV events in IDEAL was 13% lower (P=0.02) in the aggressively treated group, which achieved an LDL cholesterol level of 81 mg/dL, than in the less aggressively treated group, in which the LDL cholesterol was 104 mg/dL.
The case in favor of achieving very low levels of LDL cholesterol is now overwhelming. To achieve these newly recommended LDL cholesterol targets in many people, it is necessary to use the highest doses of the most effective statins. Such levels are most unlikely to be achieved by the unmonitored use of low doses of statins purchased OTC. The unmonitored use of OTC statins also will make it most unlikely that other lipid abnormalities such as a low level of HDL cholesterol will be identified and treated.
| Failure to Address a Low Level of HDL Cholesterol |
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The particular importance of identifying low levels of HDL cholesterol in people treated with a statin is highlighted by the observation (see below) that statins do not eliminate the increased CV risk that is attributable to the low HDL cholesterol level. Indeed, there is growing consensus that cholesterol-related CV risk needs to be attacked simultaneously on 2 fronts: by reducing the level of LDL cholesterol with a statin while raising HDL cholesterol with niacin or a fibrate. This view has been strengthened by the results of the INTERHEART (Effect of Potentially Modifiable Risk Factors Associated With Myocardial Infarction in 52 Countries) study19 in which the ratio of apolipoprotein B to apolipoprotein A-I (reflecting the ratio of LDL to HDL) was of enormous power in predicting future myocardial infarction in a large cohort of subjects of widely differing ethnic origin.
A low level of HDL cholesterol is a well-recognized component of the dyslipidemia associated with insulin-resistant states such as type 2 diabetes and the metabolic syndrome.20,21 The prevalence of these disorders (and the associated low HDL cholesterol) is increasing alarmingly, largely as a consequence of a worldwide epidemic of abdominal obesity.22 In people with these insulin-resistant states, it may be argued that raising the level of HDL cholesterol is even more important than lowering the level of LDL cholesterol. Ideally, both LDL and HDL should be targeted.
Statins reduce CV risk in virtually all groups of people in whom they have been studied. This includes people with low levels of HDL cholesterol. However, although a statin will reduce CV risk in those with low HDL cholesterol levels, the HDL cholesterol level before statin therapy is started remains predictive of CV events even after statin therapy has been initiated. This observation has been made in several large-scale statin trials conducted in both a primary and secondary prevention setting.
The inability of statins to eliminate the CV risk associated with low levels of HDL cholesterol was apparent in a primary prevention setting with pravastatin in the West of Scotland Coronary Prevention Study (WOSCOPS)23 and in a secondary prevention setting with pravastatin in the pooled analysis of the Long-Term Intervention With Pravastatin in Ischemic Disease (LIPID) and the Cholesterol and Recurrent Events (CARE) trials24 and with simvastatin in the Heart Protection Study (HPS).25 In all of these trials, treatment with a statin largely eliminated the influence of baseline LDL cholesterol as a predictor of coronary events, regardless of whether the HDL cholesterol was high or low. In each of these studies, however, the baseline level of HDL cholesterol remained as predictive of events in the statin-treated group as in the placebo group (Figure 4).
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Thus, a low level of HDL cholesterol is an important target for therapy to reduce CV risk; a low level of HDL cholesterol is becoming increasingly common; and it has been a consistent finding that a low level of HDL cholesterol before statin therapy is begun remains predictive of CV events even after statin therapy has been initiated. Therefore, it is apparent that to maximize risk reduction, a low level of HDL cholesterol requires therapy beyond a statin. Such action is most unlikely to be initiated in someone taking statins OTC.
| Conclusions |
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A question was posed at the beginning of this article: Is it desirable to make statins available OTC? Clearly, the answer is no.
| Acknowledgments |
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Dr Rye is a National Heart Foundation of Australia Principal Research Fellow.
Disclosures
Drs Barter and Rye have received research grants from Pfizer Pharmaceutical; served on the speakers bureau for and received honoraria from Pfizer, AstraZeneca, Abbott, and Fournier; and worked as a consultant or on the advisory board for Prizer, AstraZeneca, and Abbott.
| References |
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Drs Barter and Rye articulate several cogent arguments for opposing over-the-counter (OTC) access to statins. I agree in principle with their observations: Unsupervised OTC statin use would be a misstep in high-risk patients, who should be under a clinicians care, and in low-risk patients, for whom the risk-to-benefit ratio may be unfavorable; the risk associated with low high-density lipoprotein cholesterol (HDL-C) is underappreciated; and we must give thought to raising HDL-C as a therapeutic strategy. In my opinion, addressing these issues does not necessarily require abandoning OTC statins. Although Drs Barter and Rye note that statins failed to eliminate the association of cardiovascular risk with low HDL-C in several trials, it is doubtful that any single therapy could do so. Nevertheless, in the Air Force/Texas Coronary Atherosclerosis Prevention Study, excess cardiovascular risk was greatly reduced in a below-average HDL-C population by lovastatin. It is important to emphasize that OTC statins are intended to target a specific, and sizable, population of at-risk patients: moderate-risk individuals whose risk is demonstrably undertreated at present. Can we use OTC statins to improve risk-reducing efforts in this group? Unfortunately, we cannot completely anticipate how consumers would respond to OTC statins or what the impact would be in the United States, although we can continue to watch the United Kingdoms OTC initiative for perspective. In summary, the challenge posed by the Food and Drug Administration committees may be stated as follows: Can we ensure that OTC statins will get into the hands of those who are most likely to benefit while minimizing the risks for side effects and misuse? Giving patients greater autonomy over their own therapeutic choices can be beneficial, but one must acknowledge that there are many important questions about OTC statins that remain to be answered.
| Footnotes |
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